Ahmed A. Al-Taani

Status of trace metals in surface seawater of the Gulf of Aqaba, Saudi Arabia

The Gulf of Aqaba (GoA) is of significant ecological value with unique ecosystems that host one of the most diverse coral communities in the world. However, these marine environments and biodiversity have been threatened by growing human activities. We investigated the levels and distributions of trace metals in surface seawater across the eastern coast of the Saudi GoA. Zn, Cu, Fe, B and Se in addition to total dissolved solids and seawater temperature exhibited decreasing trends northwards. While Mn, Cd, As and Pb showed higher average levels in the northern GoA. Metal input in waters is dependent on the adjacent geologic materials. The spatial variability of metals in water is also related to wave action, prevailing wind direction, and atmospheric dry deposition from adjacent arid lands. Also, water discharged from thermal desalination plants, mineral dust from fertilizer and cement factories are potential contributors of metals to seawater water, particularly, in the northern GoA.

Seasonal variations in water quality of Al-Wehda Dam north of Jordan and water suitability for irrigation in summer

Al-Wehda dam is an impoundment on the Yarmouk River basin north of Jordan, which came recently into operation. The reservoir is designated to provide water for agricultural, domestic, and industrial uses. Evaluation of seasonal trends in water quality of Al-Wehda dam over the year 2010 showed strong influences by weathering and leaching of geologic units along with discharge of effluents from the adjacent agricultural lands. Seasonal trends in TDS level showed slight variations, though its concentrations have been affected by events of rainfall and evaporation. The presence of total nitrogen (TN) and total phosphorus (TP) promoted the development of photosynthetic algae. Temporal fluctuations in TN, TP, chlorophyll a, COD, and BOD have been observed with peaks occurred in spring season. TN to TP ratios varied seasonally with a minimum ratio observed in spring concurrent with algal bloom. Eutrophication tends to occur throughout the year, though its intensity increased in springtime. A variety of water quality parameters has been used to evaluate water for irrigation use during summer time when the water demand for irrigation increased. Of all parameters evaluated, Na% and TH indicated that the reservoir water is not suitable for irrigation purposes.

Atmospheric dry deposition of mineral dust to the Gulf of Aqaba, Red Sea: rate and trace elements.

Atmospheric dry deposition to the Gulf of Aqaba (GoA) is particularly a significant source of trace elements. Amid desert regions, the Gulf receives high fluxes of mineral dust with an average rate of 34.68 g/m(2)/year measured in 2012. Patterns of dry deposition showed seasonal fluxes with highest rates observed in summer and lowest in winter. The observed variations were attributed to wind direction, timing of deposition and sources of dust. The average dry fluxes of Al, Fe, Mn, Cr, Cd, Cu, Pb and Zn were 551, 440, 10.29, 1.42, 0.04, 0.68, 1.42 and 4.02 mg/m(2)/year, respectively. While the dry deposition fluxes were enriched in Cd, Cu, Pb and Zn indicating their dominant anthropogenic sources, they appeared to be less influenced compared to the neighboring Mediterranean area and other industrial countries, but were similar to or slightly higher than those in remote areas. The enrichment values for Fe and Mn were low, consistent with their crustal origin. The fluxes of all elements suggested the impacts of both crustal (due to climate change) and anthropogenic sources became stronger in this region. The Sahara dust was probably a minor contributor to dry deposition in the GoA.

Hydrochemical Facies and Ionic Ratios of the Coastal Groundwater Aquifer of Saudi Gulf of Aqaba: Implication for Seawater Intrusion

ABSTRACT Batayneh, A.; Zaman, H.; Zumlot, T.; Ghrefat, H.; Mogren, S.; Nazzal, Y.; Elawadi, E.; Qaisy, S.; Bahkaly, I., and Al-Taani, A., 2014. Hydrochemical facies and ionic ratios of the coastal groundwater aquifer of Saudi Gulf of Aqaba: implication for seawater intrusion. It is now fairly documented that major ion chemistry of the groundwater can be used to determine an interaction between the groundwater and saline water in the costal aquifers, and that there exists a relationship between total dissolved solids and Cl−, Na+, Mg2+, and concentrations of groundwater. This hypothesis is tested on an aquifer located along the Saudi Gulf of Aqaba coast (Red Sea). Groundwater samples collected from 23 locations show the abundance of ions in the order of: Ca2+ > Na+ > Mg2+ > K+ = Cl− > > > . The Piper trilinear diagram reveals two dominant clusters, i.e. the Ca2+–Cl−– facies and the Na+–Cl−– facies. Besides the major chemical compositions, ionic ratios ( /Cl−, Na+/Ca2+, Na+/Cl−, Ca2+/Cl−, Mg2+/Cl−, K+/Cl−, /Cl−, Ca2+/Mg2+, Ca2+/ , and Ca2+/ ) are used to evaluate the effects of saline water intrusions. Factor analysis of the studied samples demonstrates that changes in the groundwater composition are primarily controlled by mineral dissolution, human activities, weathering of marine sediments, evaporation/salinization of groundwater, and the residence time of water. An attempt has been made to identify hydrochemical processes accompanied with the current intrusion of seawater through the use of ionic exchanges. Following this procedure, about 7.97% mixing rate of seawater intrusion has been estimated for the month of March 2012. Furthermore, the seawater mixing index has also been applied, which resulted in a range of values from 0.395 to 7.922. These results determine 13 of 23 groundwater samples (57%) as saline, with electrical conductivity > 3000 μS/cm.

Modeling the risk of groundwater contamination using modified DRASTIC and GIS in Amman-Zerqa Basin, Jordan

Amman-Zerqa Basin (AZB) is the second largest groundwater basin in Jordan with the highest abstraction rate, where more than 28% of total abstractions in Jordan come from this basin. In view of the extensive reliance on this basin, contamination of AZB groundwater became an alarming issue. This paper develops a Modified DRASTIC model by combining the generic DRASTIC model with land use activities and lineament density for the study area with a new model map that evaluates pollution potential of groundwater resources in AZB to various types of pollution. It involves the comparison of modified DRASTIC model that integrates nitrate loading along with other DRASTIC parameters. In addition, parameters to account for differences in land use and lineaments density were added to the DRASTIC model to reflect their influences on groundwater pollution potential. The DRASTIC model showed only 0.08% (3 km2) of the AZB is situated in the high vulnerability area and about 30% of the basin is located in the moderately vulnerable zone (mainly in central basin). After modifying the DRASTIC to account for lineament density, about 87% of the area was classified as having low pollution potential and no vulnerability class accounts for about 5.01% of the AZB area. The moderately susceptible zone covers 7.83% of the basin’s total area and the high vulnerability area constitutes 0.13%. The vulnerability map based on land use revealed that about 71% of the study area has low pollution potential and no vulnerability area accounts for about 0.55%, whereas moderate pollution potential zone covers an area of 28.35% and the high vulnerability class constitutes 0.11% of AZB. The final DRASTIC model which combined all DRASTIC models shows that slightly more than 89% of the study area falls under low pollution risk and about 6% is considered areas with no vulnerability. The moderate pollution risk potential covers an area of about 4% of AZB and the high vulnerability class constitutes 0.21% of the basin. The results also showed that an area of about 1761 km2 of bare soils is of low vulnerability, whereas about 28 km2 is moderately vulnerable. For agriculture and the urban sector, approximately 1472 km2 are located within the low vulnerability zone and about 144 km2 are moderately vulnerable, which together account for about 8% of the total agriculture and urban area. These areas are contaminated with human activities, particularly from the agriculture. Management of land use must be considered when changing human or agricultural activity patterns in the study area, to reduce groundwater vulnerability in the basin. The results also showed that the wells with the highest nitrate levels (81–107 mg/l) were located in high vulnerable areas and are attributed to leakage from old sewage water.

Effects of pollution on the geochemical properties of marine sediments across the fringing reef of Aqaba, Red Sea.

The Gulf of Aqaba is of significant strategic and economic value to all gulf-bordering states, particularly to Jordan, where it provides Jordan with its only marine outlet. The Gulf is subject to a variety of impacts posing imminent ecological risk to its unique marine ecosystem. We attempted to investigate the status of metal pollution in the coastal sediments of the Jordanian Gulf of Aqaba. The distribution of Cd, Cr, Zn, Cu, Pb, Al, Fe, and Mn concentrations were determined in trapped and bottom-surface sediments at three selected sites at different depths. In addition, monthly sedimentation rates at varying water depths were also estimated at each sampling site using sediment traps. The high concentrations of Cd, Cr, Zn were recorded at the Phosphate Loading Birth (PLB) site followed by the Industrial Complex (IC) site indicating their dominant anthropogenic source (i.e., the contribution of industrial activities). However, Fe, Al, and Mn contents were related to inputs from the terrigenous (crustal) origin. Except for Al, Fe and Mn at the PLB site, the concentrations of metals exhibited a decreasing trend with increasing water depth (distance from the shoreline). The PLB site also showed the highest sedimentation rate which decreased with increasing water depth. The Enrichment factors (EFs) showed that Cd was the most enriched element in the sediment (indicating that Cd pollution is widespread), whereas the least enriched metal in sediments was Cu. EF values suggested that the coastal area is impacted by a combination of human and natural sources of metals, where the anthropogenic sources are intense in the PLB site (north of Gulf of Aqaba). The MSS area is potentially the least polluted, consistent with being a marine reserve. The IC sediments have been found to be impacted by human activities but less intensely compared to the PLB area. These results suggested that there are two sources of metals in sediments; the primary source is likely closer to PLB, while the secondary is nearby the IC.

Evaluating the potential of sediments in Ziqlab Reservoir (northwest Jordan) for soil replacement and amendment

Abstract Surface sediments of Ziqlab Reservoir, northwest Jordan, were evaluated to characterize trace element distributions and sources related to various physicochemical variables. Trace element distribution is determined by texture, parent material in the catchment, and anthropogenic activities. The suitability of reservoir sediment for replacing or amending soil was assessed by comparing sediment characteristics to natural soils. Results suggest that the sandy facies can be used as artificial soils, whereas clayey facies can be utilized as fertilizer for poor quality soils in Jordan. The fine-grained sediment fraction is associated with (1) high abundance of clay minerals with high cation exchange capacity and available micronutrients; (2) occurrence of kaolinite, montmorillonite–illite, vermiculite, and smectite; and (3) optimal pH values for availability of most micronutrients. Among the trace elements measured, total nickel and cadmium slightly exceeded recommended safe levels for soils, but the high concentrations may decline when sediments are exposed to air. If removal of the bottom sediments of Ziqlab Reservoir becomes economically feasible, it would extend the reservoir lifespan, improve water quality, compensate for soil scarcity in some regions, and enhance soil productivity.

Environmental Assessment of the Gulf of Aqaba Coastal Surface Waters, Saudi Arabia

ABSTRACT Batayneh, A.; Elawade, E.; Zaman, H.; Al-Taani, A.A.; Nazzal, Y., and Ghrefat, H., 2014. Environmental assessment of the Gulf of Aqaba coastal surface waters, Saudi Arabia. A research project on the Saudi Gulf of Aqaba was initiated in January 2012 to evaluate, protect, and develop a proper management plan for sustainable use of water resources in the coastal region. Within the framework of this project, a total of 85 surface water samples was collected and investigated to document the surface distribution of the hydrographical parameters (including water temperature, salinity, density, hydrogen ion concentration, and dissolved oxygen) as well as concentration of the nutrient salts (ammonium, nitrite, nitrate, phosphate, and silicate). The results show no thermocline or thermal pollution in the studied water and that they are mostly well oxygenated. In addition, no significant variations in the pH and salinity values have been observed. Relatively low levels of nitrogen, phosphorus (in the dissolved and total forms), and reactive silicate are observed. Inorganic nitrogen is found in the order of NO3-N > NO2-N > NH4-N. On the basis of the relatively low level of nutrient salts, the Gulf of Aqaba coastal water is classified as oligotrophic to mesotrophic in nature, and the study area is not yet seriously affected by contamination in spite of rapid population growth and fast infrastructural/recreational development during the past decade.

Trend analysis in water quality of Al-Wehda Dam, north of Jordan

Temporal status and trends in water quality of Al-Wehda Dam, Jordan, from 2006 to 2012 indicate that the dam is subject to a combination of impacts from rainstorm and agricultural runoffs. It also revealed that mineral dissolution, sediment load, rainfall events, evaporation, and water-level fluctuation are the major contributors to variations in water quality. The water chemistry of the impounded Al-Wehda Reservoir showed that Na, Ca, Mg, HCO3, and Cl are the principal ions, reflecting the dominance of carbonate weathering, with some contribution of silicates. The pH values showed a cyclic pattern with highest values observed in the spring seasons. Total dissolved solids (TDS), Ca, Mg, and HCO3 are primarily related to leaching and evaporation, with elevated levels that occurred in the rainy winter months. In contrast, seasonal patterns in Na, K, Cl, and NH4–N contents showed decreased values in winter. Peaks in NO3–N observed in winter are strongly associated with agricultural runoff. Fluctuations in chlorophyll-a level were coincided with low ratio of total nitrogen (TN) to total phosphorus (TP). Seasonal variations in organic matter content were also apparent, with peaks that generally occurred in spring through early fall corresponding with high algal growth. On an annual basis, the vast majority of water quality data have generally declined, particularly, in 2011. However, it is not clear whether these decreases are related to change in management practices within the Yarmouk basin, or protective measures have been implemented. Comparison of in-lake and post-dam water quality from 2009 to 2011 showed variation in concentrations, where Ca, HCO3, NO3–N, Mg, and TDS showed relatively greater post-dam values than in-lake water, whereas pH, Na, Cl, K, COD, BOD5, and chlorophyll-a were consistently lower in post-dam water. This comparison emphasizes the importance of self-purification capacity of Al-Wehda Dam in reducing some contaminants.

Investigation of desert subsoil nitrate in Northeastern Badia of Jordan

High levels of naturally occurring nitrate were observed under desert pavement surfaces in NE Badia of Jordan. The subsoil nitrate inventory varies from about 24,351 to 28,853 kg NO(3)(-)/ha to a depth of 60 cm which is more than two times greater than nitrate in nonpavement soils, although both soils occurred within similar landscape and microclimate conditions. The results indicated that pavement particle size and cover percent are the primary factors contributing to the observed variations in nitrate accumulation. Desert pavement soils fully covered with fine clasts showed higher nitrate concentrations compared to soils moderately covered with coarse-grained pavements. The results also showed that high levels of nitrate were generally reached between 20 and 30 cm depth before the concentrations decreased. Chloride showed distribution profiles similar to those of nitrate. No observable difference was observed in nitrate level under desert pavement with abundant lichens compared to non-lichen pavement surface.